I will throw this on the table (and quickly hide my hand behind my back): If the price model (IMHO correctly) is connected to the actual costs of the search, w

I will throw this on the table (and quickly hide my hand behind my back): If the price model (IMHO correctly) is connected to the actual costs of the search, why not make a "searches account"? You pay 5$ per month as a "baseline" and each first of the month 200 searches are credited on your account. Then, if you use less than 200 searches, at the end of the month you have a credit that goes over to next month. If your credit goes to 0 within a month, you can buy "packets" of searches, 5$ for 200, 10$ for 500, or something like that, and recharge your account.